Dark-light boxMice were introduced into the dark compartment (<10lux, length x width x height: 25 x 25 x 30 cm) of a dark light box. 60 s later the motorized door opened providing access to an identical sized compartment which was brightly lit (625 lux) and left open for 10 min. Visits to, and time spent in the light compartment were counted when the body reference point of a mouse protruded at least 2 cm into the light compartment away from the door.